A Food and Drug Administration panel backed a novel, noninvasive device that uses an electrical field designed to blast apart cancer cells as a potential treatment for brain cancer amid concerns about how well the device works.

The device, called the NovoTTF (for tumor treating fields), was designed by a private firm, NovoCure Ltd., which has operations in Israel and the U.S. It is being developed for use in patients with glioblastoma, a common form of brain cancer, initially for use after standard treatments fail.

The panel of non-FDA medical experts voted 7 to 3 in favor of a question that asked whether the benefits of the device outweighed the risks. Two panel members abstained from voting. The panel unanimously said the product was safe, but split on whether the product is effective.

The vote amounts to a recommendation that the FDA approve the device. The FDA usually follows its panel's advice but isn't required to. The agency is expected to make a decision in about three months.

One panel member who abstained, Sarah Hollingsworth Lisanby, a brain-stimulation expert who chairs the psychiatry department at Duke University, said the technology "could be a real breakthrough" but said the clinical study submitted by the company didn't prove it was effective. Still, she said she could support use of the product after all other options failed to successfully treat brain cancer.

William Doyle, a NovoCure director, said the company would work with the FDA on the product label to make certain it is clear the device should only be used in patients after standard treatments fail and not in place of initial chemotherapy.

Patients diagnosed with glioblastoma typically undergo surgery to remove as much of the tumor as possible. Most then receive radiation and chemotherapy drugs. Many patients also receive Roche Holdings AG's Avastin, a drug that is designed to block blood-vessel growth that causes tumors to grow.

Glioblastomas are difficult to treat and are the most lethal type of brain cancer. Most patients die within five years of diagnosis, and many don't live much more than six months from the time a tumor starts growing again after initial treatment.

NovoCure's device is designed to disrupt the division of cancer cells in the brain using alternating electrical fields delivered by means of insulated electrodes applied to the surface of the scalp inside what looks like a large white bandage. The device is powered by a battery pack that is placed in an over-the-shoulder bag that's a bit smaller than a typical laptop computer. The electrical fields generated by the device don't affect healthy cells in the brain that don't divide. The main side effect with the device is scalp irritation.

Patients in a clinical study of the device were instructed to remain connected to it 20 hours each day. The study involved 237 patients in Europe and the U.S. with advanced brain cancer who had previously been treated with standard therapies.

About half were given the NovoCure device while the other half were given additional chemotherapy. Patients in both groups lived for a little more than six months. However, the FDA said there appeared to be a "small trend" toward higher overall survival among U.S. patients. The study also included patients from Israel and Europe.

Richard Fessler, the vice chair of neurosurgery at Northwestern University, voted to support the device saying, "it's clearly better than nothing and these people are at the end of the line."

The company said patients using the device had a better quality of life with a reduction in side effects related to new rounds of chemotherapy typically given when cancer recurs. Patients with the device, who spoke during Thursday's meeting, urged the FDA panel to recommend approval, with one patient describing his quality of life was "fabulous."

Novocure's product is currently being studied in a different clinical trial in newly diagnosed glioblastoma patients in addition to standard treatments as well as in non-small cell lung-cancer patients.